A new look toward crown-to-implant ratio.

PURPOSE: To clarify how crown-to-implant ratio (C-I ratio) influences the bone biomechanically with its two components: crown height and implant length. METHODS: This three-dimensional finite element study was performed in two phases. The first phase aimed to show the influence of the C-I ratio on the stresses in the peri-implant bone and the second phase to reveal the impact of each of the two components of the C-I ratio: crown height and implant length. During analyses, all models were subject to three different loading conditions - axial, buccolingual, and oblique. RESULTS: The crown-to-implant ratio was significantly influential on stress distribution in the peri-implant bone. However, the crown's height was significantly more prominent than the length of the implant. The most substantial amount of stress was seen when long crowns were combined with off-axial loads. Being mostly dominated by the height of the crown and far less by the implant's length, the C-I ratio is not balanced and seems not to be a predictive parameter in implant dentistry. CLINICAL SIGNIFICANCE: Crown-to-implant ratio is recommended to be assessed by its two components: crown height and implant length because the former impacts stresses significantly more than the latter.